In a belt style filtering apparatus, a contaminated fluid is directed into an endless belt conveyor wherein the fluid passes through the belt and at least some contaminants do not pass through the belt wherein these contaminants, such as the large particles, are carried away on the belt. The fluid can then be directed into another filtering arrangement to remove other contaminants such as the finer particles.
In these belt style filtering apparatus, the contaminated is directed to the belt by gravity wherein the fluid engages the belt from above and gravity urges the fluid through the belt and into a containment vessel. The belt moves generally perpendicular to this flow or horizontally and the belt conveys the contaminants cross-wise from under this flow of contaminated fluid. The hinge belt is configured to allow the liquid and a designated size of small particles to pass through the belt, but not a designated size of large particles. As can be appreciated, this belt configuration and the designated particle sizes can vary based on the contaminants to be filtered. For example only, machining operations of different types of metal produce different sized and shaped “chips” from long spiraled chips to fine particles wherein the dividing line between these “large” and “small” particle sizes can vary significantly to accommodate the particular chip configuration.
The hinge belt filters the large particles from the liquid, and carries them away for discharge in a collection bin. The partially cleaned fluid flows from the hinge belt into a tank. The filtering apparatus can further include a secondary filtering arrangement for these smaller particles that have passed through the belt. In this respect, the system can include a rotating drum system with a filtering screen that is supported within the tank and is partially immersed in the partially cleaned fluid in the tank. The partially cleaned fluid or liquid in the tank is urged toward the drum in that the cleaned fluid is pumped from the tank by way of the tank outlet being positioned inside the drum. As a result, the partially clean fluid flows into the drum by flowing through the screen wherein the filtering is completed and the fluid inside the drum is “clean” fluid wherein a substantial portion of a desired range of solids have been removed from the fluid. As is known, this “clean” fluid does not need to be 100% clean which is typically unnecessary.
The filtered or “clean” liquid flows axially out of the drum through the outlet opening in one end wall of the drum and an adjacent wall of the tank. A portion of this filtered liquid can also be used to help clean the screen extending about the drum. This is accomplished by directing some of this filtered liquid, under pressure, to a spray nozzle facing the drum screen in order to dislodge any particles or chips that may be clinging to this screen thereby cleaning the screen of these collected particles. These particles or chips, together with other entrained particles in the fluid settle out of the liquid and drop to the bottom of the tank or reservoir. However, as can be appreciated, these entrained particles need to be removed or they would build up on the bottom of the tank and eventually affect the performance of the filtering system by, for example, seizes one or more moving components.
These remaining contaminants can be removed manually and often were in prior art system. As can be appreciated, this can be costly and can result in down time for the filter system. Some prior art systems have attempted to remove these contaminants by way of mechanical systems such as drag bars configured to move along the bottom of the reservoir. These drag bars can be connected to separate mechanical systems or in some cases can be mechanically coupled to the belt.
More particularly, these drag bars can be a separate system moving along the bottom of the tank. In another prior art arrangement, the drag bars are secured to the outside of the hinge belt. However, in this arrangement, the small particles between upper and lower paths in the tank can get trapped, and will settle and collect on the inside of the hinge belt, causing eventual jamming or blockage in the system ultimately resulting in manual cleaning and down time of the system.
In other prior arrangement, the drag bars are secured to the chains of a drag unit which is separate from the hinge belt, which is typically located above the drag unit. While this arrangement avoids the trapped particles difficulties of the first mentioned prior arrangement, it results in substantially significant expense, complexity and space penalties, resulting from the need to provide two endless conveyor arrangements including corresponding supports and drive elements.